Question $4.$ A basic microscope can be made with a combination of convex and concave lenses. Ine objective lens is the one closest to the object you are looking at and the eyepiece lens is the one closest to your eye or camera. Imagine the object you are looking at is a a $100m$ big cell or organism.

Figure $4$

If the distance from the object to the objective; $p_1=4cm,$ and focal length $f_1=\frac{1}{20}cm=0\mathrm{.}05cm$ distance from the eyepiece to your eye$/$camera$,q_2=1cm,$

a$)$ Use the lens equation $\frac{1}{f}-\frac{1}{p}+\frac{1}{q}$ to solve for the object distance $(q_1)$ for the first lens and magnification $M=-\frac{q}{p}$ :